首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   2956篇
  免费   265篇
  国内免费   9篇
耳鼻咽喉   35篇
儿科学   91篇
妇产科学   148篇
基础医学   467篇
口腔科学   24篇
临床医学   444篇
内科学   674篇
皮肤病学   58篇
神经病学   140篇
特种医学   65篇
外科学   274篇
综合类   51篇
一般理论   10篇
预防医学   252篇
眼科学   58篇
药学   199篇
中国医学   4篇
肿瘤学   236篇
  2023年   18篇
  2022年   20篇
  2021年   56篇
  2020年   42篇
  2019年   70篇
  2018年   77篇
  2017年   56篇
  2016年   66篇
  2015年   76篇
  2014年   87篇
  2013年   138篇
  2012年   208篇
  2011年   200篇
  2010年   152篇
  2009年   125篇
  2008年   181篇
  2007年   199篇
  2006年   177篇
  2005年   196篇
  2004年   171篇
  2003年   149篇
  2002年   159篇
  2001年   78篇
  2000年   73篇
  1999年   61篇
  1998年   22篇
  1997年   27篇
  1996年   18篇
  1995年   23篇
  1994年   17篇
  1993年   5篇
  1992年   33篇
  1991年   22篇
  1990年   29篇
  1989年   19篇
  1988年   18篇
  1987年   22篇
  1986年   23篇
  1985年   20篇
  1984年   14篇
  1983年   10篇
  1982年   8篇
  1981年   10篇
  1980年   8篇
  1979年   11篇
  1978年   7篇
  1977年   4篇
  1976年   4篇
  1975年   3篇
  1972年   3篇
排序方式: 共有3230条查询结果,搜索用时 328 毫秒
1.
Legionella pneumophila is a common cause of sporadic community-acquired pneumonia, but culture-proven legionellosis is rarely diagnosed. There is no laboratory test for Legionnaires' disease that can detect all patients with the disease. Culture is the standard diagnostic method and should be initiated as soon as possible in suspected cases. We describe a rare case of community-acquired pneumonia caused by L. pneumophila serogroup 6. A 77-year-old man was admitted to a tertiary care hospital because of high fever, productive cough, and progressive dyspnea. Chest radiography showed bilateral pneumonia, which led to respiratory failure necessitating mechanical ventilatory support. Despite antibiotic therapy, his condition continued to deteriorate and acute renal failure also developed. Urine was negative for L. pneumophila. Culture of the sputum yielded L. pneumophila serogroup 6, although there was no elevation of the serum antibody titer. Pneumonia resolved gradually and he was extubated after treatment with levofloxacin followed by erythromycin. L. pneumophila other than serogroup 1 should be included in the differential diagnosis of patients with suspected atypical community-acquired pneumonia.  相似文献   
2.
BACKGROUND/PURPOSE: Abdominal nontuberculous mycobacterial infection is a rare condition. Continuous ambulatory peritoneal dialysis (CAPD)-associated peritonitis is the most common manifestation of infection due to nontuberculous mycobacteria (NTM). There are limited data on the clinical manifestations of nontuberculous mycobacterial infection. This study investigated the diagnostic features, clinical presentation, mycobacteriology, treatment and outcome of all abdominal NTM infections treated over a 7-year period at a major teaching hospital in Taiwan. METHODS: The medical records of all patients with a diagnosis of abdominal NTM infection from January 1997 through to December 2003 were retrospectively reviewed. RESULTS: All 11 patients with abdominal NTM infections identified during the 7-year period were included. Among these patients, six were male and five were female, with a mean age of 64.5 years. The disease manifested as peritonitis (9 patients, 82%), splenic abscess (1, 9%), or perirenal abscess (1, 9%). Most patients (73%) had underlying malignancy, most often hepatoma (45%). Immunocompromised status (liver cirrhosis, malignancy, acquired immunodeficiency syndrome) was noted in 10 patients (91%). None of our patients who developed NTM peritonitis had received CAPD. The peritoneal fluid appearance varied considerably, with no particular predominance of clear, turbid, bloody, or chylous findings. Rapidly growing mycobacteria were the major etiology (46%) of abdominal NTM infection, and Mycobacterium abscessus played a major role (27%). Overall, eight patients died, and only one patient survived longer than 1 year. Seven patients (64%) died before diagnosis. CONCLUSION: Abdominal NTM infection is frequently overlooked because of its rarity and nonspecific symptoms, with consequent delays in diagnosis and treatment. In immunocompromised patients with ascites from any cause (liver cirrhosis, malignant ascites, etc.), NTM peritonitis should be considered early in the differential diagnosis of symptoms including fever, abdominal pain and weight loss. The poor prognosis of abdominal NTM infection appears to be related to the severity of underlying conditions, most often malignancy.  相似文献   
3.
The in vitro DNA amplification technique of polymerase chain reaction was used to evaluate the possible presence of human papillomavirus (HPV) in small cell carcinoma of the uterine cervix. None of the 12 cases examined contain detectable amounts of either HPV type 16, 18, 31, or 33 DNA. On the other hand, HPV types 16 and 18 DNA were found in 14 (93.3%) and 9 (60.0%) of 25 invasive cervical squamous carcinoma tissues. The results seem to suggest that these types of HPV are not present or are present in extremely small quantities in cervical small cell carcinoma. Such an absence of HPV DNA makes it unlikely that these types of HPV play any etiological role in the pathogenesis of cervical small cell carcinoma.  相似文献   
4.
5.
6.
A C Wang  S Hsueh  C F Sun 《台湾医志》1992,91(11):1054-1058
This paper reports the treatment results of 50 symptomatic females who had clinical features of squamous papillae and histologic evidence of koilocytosis. Either a carbon dioxide laser or a single application of trichloroacetic acid (TCA) was used to treat these patients. All of the patients were alternately and prospectively randomized into one of two groups. Twenty-three of the 25 women treated by laser and 10 of the 25 women treated by TCA had resolution of either the symptoms or the vulvar lesions in a follow-up period ranging from six to 22 months. Hence, we were able to control the symptoms and lesions in 92% of the women following initial laser treatment and 40% of the women following a single application of TCA. In addition, cosmetic results were satisfactory, and complications were minimal in the laser-treated group of patients. However, human papillomavirus DNA was still detected three to four weeks after treatment in 24% of the women treated by laser and 64% of the women treated by TCA. Whether they are at a higher risk of recurrence as compared to those without detectable viral DNA remains to be determined.  相似文献   
7.
An excess of blood loss and persistence of intraepithelial neoplasia after cervical conization occur with some frequency. Contact Nd:YAG laser conical excision of the uterine cervix is a new technique designed to remedy those problems. In this study, 36 women with histologically confirmed cervical intraepithelial neoplasia were treated with cylindrical excision of the uterine cervix with a contact Nd:YAG laser. The results were compared with those in 30 women who had similar lesions and were treated with the CO2 laser. Use of the Nd:YAG laser resulted in less intraoperative blood loss (mean +/- SD, 3.12 +/- 0.28 vs. 30.3 +/- 2.12 mL for the CO2 laser, P less than .01) and less postoperative blood loss. The volume of early bleeding was 6.23 +/- 1.21 vs. 20.13 +/- 2.24 mL for the CO2 laser (P less than .01), and that of late bleeding was 5.22 +/- 2.21 vs. 31.24 +/- 0.05 mL for the CO2 laser (P less than .01). The operative time was similarly less for the contact Nd:YAG laser (6.2 +/- 2.2 vs. 20.2 +/- 1.2 minutes for the CO2 laser, P less than .01). The dimensions of the excised specimens were similar. These findings suggest that the contact Nd:YAG laser offers distinct advantages over the CO2 laser in performing cylindrical excision of the cervix.  相似文献   
8.
Contact lens fitting may be required following keratoplasty for either optical or thera‐peutic reasons. Optical indications for contact lens fitting include the correction of irregular astigmatism, high regular astigmatism, anisometropia and secondary aniseikonia, as well as simple ametropia, where the patient desires to wear contact lenses in preference to spectacles. Therapeutic lenses are not routinely fitted following kerate plasty, although this management is advised in certain cases, such as when there are protruding sutures or epithelial healing is impaired. Designing a contact lens for a patient who has undergone keratoplasty will require the practitioner to carefully assess all the relevant features of the corneal graft. In this regard, there are many factors that need to be considered including the diameter of the graft zone, the topographical relationship between the host cornea and donor cornea, the corneal (graft) toricity and the location of the graft. Special designs, such as reverse geometry lenses, or more complex contact lens modalities, such as piggyback contact lens systems, may be required to achieve success in fitting.  相似文献   
9.
On May 8–10, 1995, a workshop on chronic inhalation toxicity and carcinogenicity testing of respirable fibrous particles was held in Chapel Hill, North Carolina. The workshop was sponsored by the Office of Pollution Prevention and Toxics, U.S. Environmental Protection Agency (EPA), in collaboration with the National Institute of Environmental Health Sciences (NIEHS), the National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). The goal of the workshop was to obtain input from the scientific community on a number of issues related to fiber testing. Major issues for discussion were: (i) the optimal design and conduct of studies of the health effects of chronic inhalation exposure of animals to fibers; (ii) preliminary studies which would be useful guides in designing the chronic exposure study; (iii) mechanistic studies which would be important adjuncts to the chronic exposure study to enable better interpretation of study results and extrapolation of potential effects in exposed humans; and (iv) available screening tests which can be used to develop a minimum data set for (a) making decisions about the potential health hazard of the fibers and (b) prioritizing the need for further testing in a chronic inhalation study. After extensive discussion and debate of the workshop issues, the general consensus of the expert panel is that chronic inhalation studies of fibers in the rat are the most appropriate tests for predicting inhalation hazard and risk of fibers to humans. A number of guidances specific for the design and conduct of prechronic and chronic inhalation studies of fibers in rodents were recommended. For instance, it was recommended that along with other information (decrease in body weight, systemic toxicity, etc.), data should be obtained on lung burdens and bronchoalveolar lavage fluid analysis to assist in establishing the chronic exposure levels. Lung burden data are also important for quantifying aspects of risk assessment related to dosimetric adjustments before extrapolation. Although mechanistic studies are not recommended as part of the standard chronic inhalation studies, the expert panel stressed the need for obtaining mechanistic information as far as possible during the course of subchronic or chronic inhalation studies. At present, no single assay and battery of short-term assays can predict the outcome of a chronic inhalation bioassay with respect to carcinogenic effects. Meanwhile, several short-termin vitroandin vivostudies that may be useful to assess the relative potential of fibrous substances to cause lung toxicity/carcinogenicity have been identified.  相似文献   
10.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号